Hydraulic engine governor

ABSTRACT

In a preferred embodiment, an engine governor having a speed responsive spinner valve coupled with the engine oil pump in the engine crankcase and hydraulically connected with a slave actuator arranged to control the maximum opening of the engine throttle. An adjustable spring incorporated in the spinner valve provides a primary adjustment of the controlled maximum engine speed. Limited modification of the set speed is provided by an adjustable bleed valve located in the external portion of the hydraulic circuit to the slave unit at a point convenient for adjustment by the engine operator. Limited travel of the adjusting screw may be provided to limit the range of engine speed adjustment possible by the operator. Drain means are provided to return bleed oil to the engine sump.

United States Patent 1 Cot [ 1 HYDRAULIC ENGlNE GOVERNOR [75] lnventor: James D. Cot, Pontiac, Mich.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[221 Filed: Dec. 22, 1971.

[21] Appl. No.: 210,790

[52] US. Cl. 123/140 FG, 123/198 DB, 123/140 A, d

[ 1 Dec. 11, 1973 Primary ExaminerLaurence M. Goodridge Assistant Examiner-Ronald B. Cox Attorney-J. L. Carpenter et a1.

[57] ABSTRACT ln a preferred embodiment, an engine governor having a speed responsive spinner valve coupled with the engine oil pump in the engine crankcase and hydraulically connected with a slave actuator arranged to control the maximum opening of the engine throttle. An adjustable spring incorporated in the spinner valve provides a primary adjustment of the controlled maximum engine speed. Limited modification of the set speed is provided by an adjustable bleed valve located in the external portion of the hydraulic circuit to the slave unit at a point convenient for adjustment by the engine operator. Limited travel of the adjusting screw may be provided to limit the range of engine speed adjustment possible by the operator. Drain means are provided to return bleed oil to the engine sump.

2 Claims, 5 Drawing Figures PAIENIEBUEC 1 1 ms 3.777329 J mes 3 (a e ATTO RNEY HYDRAULIC ENGINE GOVERNOR BACKGROUND OF THE INVENTION This invention relates to hydraulic engine governors and, more particularly, to a preset speed limiting hydraulic governor having provision for limited adjust ment of theengine speed by the operator at a convenient external engine location.

It is known in the art to provide vehicle engines with hydraulic speed limiting governors which prevent the engine from being overspeeded in service and m'ay,'in addition, provide maximum operating speeds at which the vehicle may be driven. In some such governors it is known to provide a centrifugally actuated control valve known as a spinner valve which is mounted within the engine crankcase as an attachment to the oil pump. The spinner valve is hydraulically connected with an externally mounted hydraulic actuator or slave unit mechanically connected with the engine throttle. The spinner valve controls the application of lube oil pressure to the slave 'unit, which in turn controls engine speed by limiting the maximum opening of the engine throttle.

Selection of the maximum controlled engine speed in such prior art units has been accomplished by adjusting the force of a spring carried on and biasing the spinner valve within the engine crankcase. With this arrangement the controlled engine speed is set before assembly of the unit into the engine and cannot be adjusted bythe engine operator without disassembling the engine. 'While in many applications the provision of a governor that cannot easily be reset by the operatorvis desirable, there 'are'other applications in which it may be desi'rable to utilize the same type of engine and governor but 'to provide some means for at least minor modification of the engine speed settings. For example, in industrial and agricultural equipment applications of engines commonly used in road vehicles, the accuracy of the maximum governed'speed may be sufficiently importantto provide some means of making at least minor adjustments in the controlled speed after the basic speed setting of the governor has been made during engine assembly. Also, the possibility of a change in the effective speed setting after extended service due to wear or weakening of the governor spring might also give reason forthe provision of a secondary-speed adjustment capable of restoring the desired setting without disassembling the engine.

SUMMARY OF THE INVENTION The present invention involves an improvement of prior art hydraulic governors of the type described through the provision of an externally adjustable bleed valve in the hydraulic circuit between the governor control valve or spinner unit and the hydraulic actuator or slave unit. The bleed valve is preferably arranged with limited travel so that it provides a leakage path from the hydraulic connection, the size of which can be controlled within predetermined limits by the engine operator through adjustment of an adjusting screw or the like. Variation of the size of the bleed orifice in this 'manner'has the effect of modifyingthe flow required through the spinner valve in order to establish predetermined control pressures on the actuator and thus makes provision formodification of the predetermined maximum engine operating speed to which the engine .is limited by the governor. Various positions for the bleed valve are possible, including incorporation in the body of the slave unit or mounting in a separate fitting located on the exterior of the engine crankcase and forming a part of the connection between the spinner valve and slave unit.

The invention permits application of the basic type vehicle hydraulic governor in a number of other applications while retaining the basic advantage that the primary speed setting is not easily tampered with by the operator of the engine or vehicle. Limitation of the travel of the adjusting screw or the size of the orifice may be provided to prevent modification of the speed setting by the operator beyond desired limits.

These and other advantages of the invention will be more fully understood from the following description of certain preferred embodiments of the invention, taken together with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a front elevational view of an engine having governor means according to the invention with portions broken away to show certain construction elements;

' FIG. 2 is a cross-sectional view taken in the plane generally indicated by the line 2-2 of FIG. 1 and disclosing details of the engine oil pump and spinner valve;

FIG. 3 is a cross-sectional view taken in the plane indicated by the line 33 of FIG. 1 and disclosing certain details of the governor slave unit; I

FIG. 4 is afront elevational view of an engine having an alternative embodiment of governor means formed according to the invention; and

FIG. 5 is an enlarged cross-sectional view of a portion of the engine of FIG. 4, showing the arrangement of the bleed valve incorporated in a crankcase fitting.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 3 of the drawing illustrate a preferred embodiment of the invention applied to an internal combustion engine generally indicated by numeral 10. Engine 10 includes the usual cylinder block 12 and oil pan l4, whichtogether enclose the engine crankcase and oil sump. The engine additionally includes cylinder heads 16 covered by rocker covers 18 and having mounted thereon an inlet manifold 20. A carburetor22 is mounted on the inlet manifold and includes the usual throttle 24 which is movablebetween open and closed positions to control the passage of-fuel mixture into the engine, thereby controlling its speed and power.

Mounted within the engine crankcase and above'the level of lubricating oil in the oil pan is an engine driven oil pump 26, which'is connected, through means not shown, to draw oil from the oil sump. Oil pump ,26 provides pressurized lubricating oil for lubricating the various moving parts of the engine, as well as to operate the hydraulic engine governor to be subsequently ,described.

vIn the embodiment of FIGS. '1 3 the engine governor has three'main componentsz a spinner valve assembly 28 which is mounted on oil pump 26 internally of the engine and is best shown in FIG. 2, a hydraulic actuator or slave unit 30 that is mounted on the carburetor externally of the engine and is best shown in'FIG. 3, and conduit means connecting thespinner valve assembly and the slave unit, the conduit means including an internal conduit 32 and an external conduit 34 jointed by suitable fittings 36, 38 secured in the crankcase wall of the cylinder block 12.

As shown in FIG. 2, oil pump 26 includes suitable gears 40 which during engine operation deliver pressure oil to a recess 42 of the spinner valve assembly, from which it passes through passages controlled by the spinner valve 44 to a connection with the conduit 32, leading to the slave unit 30. During engine operation, the spinner valve 44 is urged in one direction through centrifugal action on a weight 46, the movement being opposed by the bias of a spring 48, the force of which is adjustable through an adjusting nut 50 carried on the spinner valve body. At low engine speeds, rotation of the spinner valve is insufficient for it to move against the force of the spring so that oil pressure is prevented from passing the valve. However, at a preset speed determined by the force setting of spring 48, the centrifugal force will be sufficient to overcome the force of the spring, moving the spinner valve rightwardly, as shown in FIG. 2, and permitting a flow of oil from the oil pump to the slave unit.

Slave unit 30 as illustrated in FIG. 3 includes a main body 52 which may be formed as a portion of the carburetor or separately attached thereto. A cover member 54 is secured to body 52 and retains therebetween a pressure responsive diaphragm 56. Diaphragm 56 is biased leftwardly by a spring 58 and connects through a telescoping link 60 with a lever 62 which is attached to the throttle shaft 64. A tension spring 66 is provided to move the throttle 24 in an opening direction whenever the vehicle accelerator pedal, not shown, is depressed by the vehicle operator.

External conduit 34 connects with the cover member 54 so that pressure oil passing through the spinner valve 44 to the conduits 32, 34 is applied against the diaphragm 56, forcing it rightwardly, as shown in FIG. 3, against the telescoping link 60 and moving the throttle lever 62 in a throttle closing direction against the force of the springs 58 and 66. When the engine speed is reduced, movement of the spinner valve 44 to the position shown in FIG. 2 closes off the further supply of pressure oil and permits the escape of pressure from the slave unit and conduits through a slot 68 provided in the spinner valve body. A control orifice 69 in the body of the spinner valve assembly 28 also aids in draining pressure oil from the conduits and slave unit.

The slave unit cover member 54 is additionally provided with a bleed valve portion 70 which includes an orifice 72 that connects the hydraulic system with a small internal recess 74. An adjusting screw 76 protrudes from the bleed valve portion for external adjustment thereof and has one end extending into the orifice 72 for adjusting the effective size thereof. A collar portion 78 on the screw 76 engages an internal shoulder to provide a stop, preventing the adjusting screw from being moved out of the orifice beyond a predetermined desired amount, thereby effectively limiting the maximum size of the bleed orifice. A drain conduit 80 con nects the internal recess 74 with the adjacent rocker cover 18 to return oil passing through the orifice 72 to the engine interior for return to the sump.

In operation, adjustment of the screw 76 varies the effective flow area of orifice 72 and thus controls the flow of oil therethrough from the hydraulic system. This, in turn, determines the rate of flow required through the spinner valve 44 to develop a pressure on the diaphragm 56 sufiicient to actuate the throttle in a closing direction and in this way varies, in the degree permitted by the limited screw adjustment and orifice size, the maximum speed at which the governor permits the engine to operate. This speed adjustment is easily made by the engine operator whenever a modification of the speed setting is called for, while the primary speed setting through adjustment of the nut 50 on the spinner valve 44 cannot be altered without removing the engine oil pan for access to the spinner valve assembly.

In FIGS. 4 and 5 there is illustrated an alternative embodiment of the invention. This embodiment is similar to that of FIGS. 1 3, differing therefromessentially only in the location of the bleed valve in the system. Thus, to avoid unnecessary repetition, identical components have been identified by primed numerals in the second embodiment and the following description refers only to those portions of the second embodiment which differ from the first.

In the alternative embodiment, the slave unit 82 is identical to that of the first embodiment except that the bleed valve portion is deleted from the cover member 84. Instead, the bleed valve is located within a block mounted fitting 86, which includes a passage 88 joining the internal and external conduits 90, 92 to provide a passage between the spinner valve assembly 28 and the slave unit 82. Fitting 86 also includes an orifice 94 connecting passage 88 with a recess 96 that is, in turn, connected through a drain passage 98 to the engine interior. An adjusting screw 100 extends into and controls the effective opening of orifice 94 and includes a collar portion 102 to control the adjustment of the screw 100.

Operation of the system is essentially as in the first embodiment, with adjustment of the screw 100 controlling the flow of bleed oil from the hydraulic system and effectively modifying the controlled engine speed established through the primary speed setting of the spinner valve spring.

While the invention has been described by reference to certain preferred embodiments chosen for purposes of illustration, it is intended to also include such changes as might be made within the scope of the novel concepts disclosed. Accordingly, the invention should not be limited except by the language of the following claims.

I claim:

1. In combination with an internal combustion engine having a throttle and an internally mounted engine driven oil pump connected with a source of oil, a speed governor including an externally mounted hydraulic actuator connected with said throttle and responsive to increasing hydraulic pressure to move said throttle in a closing direction, oil passage means connecting said hydraulic actuator with the pressure side of said oil pump, said passage means including an engine driven centrifugal governor valve assembly mounted on and driven by said oil pump and conduit means connecting said governor valve assembly with said hydraulic actuator, said governor valve assembly having centrifugal valve means operable at a predetermined engine speed to permit pressure oil from said oil pump to act upon said hydraulic actuator and close said throttle and first speed setting means connected with said centrifugal valve means and adapted to permit adjustment of said predetermined engine speed, said speed governor further comprising the improvement of second speed setting means includinga bleed valve in said passage means and disposed externally of said engine, said bleed valve providing a bleed opening for permitting a flow of oil from said passage means and being manually adjustable to vary the size of said bleed opening, and means to return to said source, oil escaping through said bleed opening, said bleed valve providing a maximum bleed opening sufficiently small to afford only a minor adjustment of engine speed by said second speed setting means as compared to the speed adjustment range of said first speed setting means, whereby the predetermined speed setting made upon assembly of the engine may be departed from by external adjustment only within a predetermined limited range, said bleed valve being mounted in a fitting in a wall of said engine and controlling flow between a main oil passage and a return passage, both formed in said fitting and comprising portions of said passage means and said oil return means, respectively, said bleed valve including an adjusting screw having a collar thereon engagable with a shoulder in said fitting to limit the maximum valve opening movement of said screw.

2. ln combination with an internal combustion engine having a throttle and an internally mounted engine driven oil pump connected with a source of oil, a speed governor including an externally mounted hydraulic actuator connected with said throttle and responsive to increasing hydraulic pressure to move said throttle in a closing direction, oil passage means connecting said hydraulic actuator with the pressure side of said oil pump, said passage means including an engine driven centrifugal governor valve assembly mounted on and driven by said oil pump and conduit means connecting said governor valve assembly with said hydraulic actuator, said governor valve assembly having centrifugal valve means operable at a predetermined engine speed to permit pressure oil from said oil pump to act upon said hydraulic actuator and close said throttle and first speed setting means connected with said centrifugal valve means and adapted to permit adjustment of said predetermined engine speed, said speed governor further comprising the improvement of second speed setting means including a bleed valve in said passage means and disposed externally of said engine, said bleed valve providing a bleed opening for permitting a flow of oil from said passage means and being manually adjustable to vary the size of said bleed opening, and means to return to said source, oil escaping through said bleed opening, said bleed valve providing a maximum bleed opening sufficiently small to afford only a minor adjustment of engine speed by said second speed setting means as compared to the speed adjustment range of said first speed setting means, whereby the predetermined speed setting made upon assembly of the engine may be departed from by external adjustment only within a predetermined limited range, said bleed valve being mounted in a portion of said hydraulic actuator and connected with said engine interior by a conduit comprising said oil return means, said bleed valve controlling flow between said actuator and said conduit and including an adjusting screw having a collar thereon engagable with a shoulder in said actuator portion to limit the maximum valve opening movement of said screw. 

1. In combination with an internal combustion engine having a throttle and an internally mounted engine driven oil pump connected with a source of oil, a speed governor including an externally mounted hydraulic actuator connected with said throttle and responsive to increasing hydraulic pressure to move said throttle in a closing direction, oil passage means connecting said hydraulic actuator with the pressure side of said oil pump, said passage means including an engine driven centrifugal governor valve assembly mounted on and driven by said oil pump and conduit means connecting said governor valve assembly with said hydraulic actuator, said governor valve assembly having centrifugal valve means operable at a predetermined engine speed to permit pressure oil from said oil pump to act upon said hydraulic actuator and close said throttle and first speed setting means connected with said centrifugal valve means and adapted to permit adjustment of said predetermined engine speed, said speed governor further comprising the improvement of second speed setting means including a bleed valve in said passage means and disposed externally of said engine, said bleed valve providing a bleed opening for permitting a flow of oil from said passage means and being manually adjustable to vary the size of said bleed opening, and means to return to said source, oil escaping through said bleed opening, said bleed valve providing a maximum bleed opening sufficiently small to afford only a minor adjustment of engine speed by said second speed setting means as compared to the speed adjustment range of said first speed setting means, whereby the predetermined speed setting made upon assembly of the engine may be departed from by external adjustment only within a predetermined limited range, said bleed valve being mounted in a fitting in a wall of said engine and controlling flow between a main oil passage and a return passage, both formed in said fitting and comprising portions of said passage means and said oil return means, respectively, said bleed valve including an adjusting screw having a collar thereon engagable with a shoulder in said fitting to limit the maximum valve opening movement of said screw.
 2. In combination with an internal combustion engine having a throttle and an internally mounted engine driven oil pump connected with a source of oil, a speed governor including an externally mounted hydraulic actuator connected with said throttle and responsive to increasing hydraulic pressure to move said throttle in a closing direction, oil passage means connecting said hydraulic actuator with the pressure side of said oil pump, said passage means including an engine driven centrifugal governor valve assembly mounted on and driven by said oil pump and conduit means connecting said governor valve assembly with said hydraulic actuator, said governor valve assembly having centrifugal valve means operable at a predetermined engine speed to permit pressure oil from said oil pump to act upon said hydraulic actuator and close said throttle and first speed setting means connected with said centrifugal valve means and adapted to permit adjustment of said predetermined engine speed, said speed governor further comprising the improvement of second speed setting means including a bleed valve in said passage means and disposed externally of said engine, said bleed valve providing a bleed opening for permitting a flow of oil from said passage means and being manually adjustable to vary the size of said bleed opening, and means to return to said source, oil escaping through said bleed opening, said bleed valve providing a maximum bleed opening sufficiently small to afford only a minor adjustment of engine speed by said second speed setting means as compared to the speed adjustment range of said first speed setting means, whereby the predetermined speed setting made upon assembly of the engine may be departed from by external adjustment only within a predetermined limited range, said bleed valve being mounted in a portion of said hydraulic actuator and connected with said engine interior by a conduit comprising said oil return means, said bleed valve controlling flow between said actuator and said conduit and including an adjusting screw having a collar thereon engagable with a shoulder in said actuator portion to limit the maximum valve opening movement of said screw. 